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The action of various anionic O , N , and S nucleophiles on 3 cyano 4,6 dinitro benzo[d]isoxazole mostly resulted in regiospecific nucleophilic substitution for the nitro group in position 4. With an excess of an nucleophilic reagent, the nitro group in position 6 was also replaced.

Tetrahydropyran-2-ones with a 4-amino function connected to a tertiary carbon atoma widely naturally occurring fragmentare constructed by a three step protocol from easily available isoxazoline 2-oxides. In the first stage, the carbon skeleton of the target product is formed upon a C,C-coupling of a silyl ketene acetal with a nitronate function, under silyl triflate catalysis. The key step of the assembly consists of the oxidative cleavage of an endocyclic NO bond of intermediate cyclic nitroso acetals with mCPBA, accompanied with lactone ring closure, and gives rise to b-nitro-d-lactones in 63-85% yields. The latter are reduced with amalgamated aluminium, to furnish the target scaffold.

Starting from the known nitrone (I), the highly potent phosphodiesterase IVb inhibitors (VII) and (X) are stereoselectively synthesized in an overall yield of 22% and 18%, respectively.

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